“At the request of members, the committee is working through additional technical changes to the legislation," said the spokesman, Aaron Fobes. "Chairman Hatch will reconvene the markup at a later date, once the bill is finalized.”

Tax fraud, and thieves' use of stolen Social Security numbers to claim fake refunds from the IRS, has become an increasing problem for the federal government in recent years. One federal watchdog found that fraudsters stole around $5.8 billion in refunds in 2013.